<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>创建图形</title>
    <style>
    
        .a {
            width: 100px;
            height: 100px;
            border-radius: 50%;
            background: #f40;
        }

        .b {
            width: 200px;
            height: 100px;
            border-radius: 50%;
            background: #f40;
        }

        .c {
            width: 0;
            height: 0;
            border-left: 20px solid #f40;
            border-top: 20px solid transparent;
            border-bottom: 20px solid transparent;
        }

    </style>
</head>
<body>
    
    <div class="a">

    </div>

    <div class="b">

    </div>

    <div class="c">

    </div>
</body>
</html>